Piston



Feb. 13, 1934. T|M|AN 1,947,177

PISTON Filed March 19, 1931 jg H 11 E J'- nl.

INVEN TOR. fi /"ah? 72 022012 BY I v I ATTORNEY.

Patented Feb. 13, 1934 UNITED STATES PATENT OFFICE.

PISTON Application March 19, 1931. Serial No. 523,753

23 Claims.

My invention'relates to engines and more p31 ticularly to a piston adapted for operation in an engine cylinder.

The object of the present invention is to preventwhat is commonly called piston slap in internal combustion engines, which is caused by movement of the piston transversely of the wrist pin axis during the operation of the engine; Where aluminum pistons are employed with cast 0 iron cylinders the initial clearance between the piston and cylinder wall is greater than the initial clearance when employing cast iron pistons, due to the fact that aluminum has a greater coefiicient of expansion than cast iron.

At the present time, aluminum pistons are more commonly employed for various reasons and consequently piston slap is more pronounced,- requiring the employment ofantipiston slap devices.

yieldingly urging the piston across the cylinder in a direction axially of the wrist pin that pivotally connects the piston with the connecting rod, thereby causing the piston to move in a 25, curved path when moved from side to side.

For a more detailed understanding'of my invention, reference may be had to the accompanying drawing which illustrates one form which myinventicn-may assume, and in which:

Figure 1 isa horizontal sectional view through anengineillustrating a piston constructed in accordance with my invention, shown in operative assembly with an engine cylinder and taken substantially on the line l--l of Figure 2, and

Figure 2 is a vertical sectional view through an engine showing a portion of the piston broken away to illustrate the means for securing-the piston thrust ring in place and taken substantially on the line 2-2 of Figure 1.

shown in the accompanying drawing consists in general of a cylinder block 10 having a plurality of cylinder bores 11 and jacket portions 12 substantially surrounding said cylinder bores. A

piston designated a whole by the reference character A is operatively associated with each cylinder and consists of a skirt portion 13 having inwardly extending bosses 14 preferably integrally carried by the skirt portion. These bosses 14 are provided with axially aligned wrist pin holes 15 for receiving the wrist pin 16 that serves to pivotally connect the piston A- with a connecting rod 17.

In engines of the character illustrated it is necessary to provide a working clearance be- In my present invention I have provided means The illustrated embodiment of my invention tween the piston and the cylinder walls and when employing aluminum pistons with a cast iron cylinder it is necessary to provide greater clearance in order to take care of the relatively greater expansion of the aluminum piston so that under normal operating conditions the piston will freely operate within the cylinder. In the operation of the engine the pressure on the piston causes the piston to press first against one side of the cylinder and then against the other, due to the angular relation between the connecting rod and the cylinder axis. This movement is very slight but is relatively rapid and in the present day high speed engines the rapidity of this movement causes an objectionable piston slap.

In order to eliminate this objectionable piston, slap it is the purpose of my invention to provide means for yieldingly urging the piston in a direction longitudinally of the central longitudinal plane of the engine and to yieldingly engage said piston with that portion of the cylinder Wall adjacent one end of the wrist pin 16. Thus when the pressure within the combustion chamber tends to tilt the piston within the cylinder or to" rockthe same by moving the same from side to side, the fact that the piston is yieldingly engaged with the cylinder wall adjacent one end of the Wrist pin causes the piston to have a rolling action with respect to said cylinder wall and'to move in a curved path so that the line of contact between the piston and the cylinder moves around the cylindrical wall of said cylinder from one side thereof to the other. This action eliminates the objectionable piston slap.

I have provided a very simple device for urging the piston in one direction axially of the wrist pin or in other words, in a direction parallel to the longitudinal plane of the engine. The piston A is provided with one or more sealing rings 18 of standard construction and the piston is provided with a groove 19 extending conveniently around the piston for receiving a piston thrust ring 20 adapted for operation in a manner hereinafter described.

This thrust ring lies within the groove 19 and is 9 preferably secured to the piston by the pin or other suitable fastening device 21 which is preferably adapted for fastening the middle'portion of said thrust ring to the piston as shown in Figure 1. This thrust ring is thus secured so as to provide arm portions 22 extending in opposite di-v rections'from the fastening device 21 and are arranged to encircle the piston. This thrust ring is split as at 23 preferably diametrically opposite the pin or fastening device 21 and the free ends of i said arm portion 22 are adapted for engagement with the cylinder wall adjacent one end of the wrist pin. This thrust ring is constructed preferably of spring steel or other suitable spring material and the said arm portions 2 are preferably tapered as shown in Figure l, the pin or fastening device 21 preferably located at the thickest portion of said thrust ring.

The inherent resilient characteristic of this thrust ring causes the end portion of each arm portion 22 to yieldingly engage said cylinder wall adjacent one end of the wrist pin and thereby urges the piston in a direction axially of the'wrist pin or in other words in a direction parallel to the longitudinal plane of the engine for yieldingly engaging that portion of the piston adjacent the other end of the Wrist pin with the adjacent cylinder wall.

It will be noted that the spring split thrust ring is so constructed and assembled with the piston that the said ring supported within the groove 19 is adapted for yieldin engagement solely with that portion of the cylinder wall adjacent one end of the wrist pin while that portion of the thrust ring adjacent the other end of the wrist pin is spaced from said cylinder wall. However, that portion of the piston ring, adjacent to that portion of the thrust ring spaced from the cylinder wall, is yieldingly engaged with the cylinder wall.

The load of each spring arm 22 is preferably applied to the cylinder wall at points substantial ly equidistant from the longitudinal plane of the engine containing the cylinder axes as indi- I, cated by the arrows 24 thereby providing spaced as lines of contact between the thrust ring and cylinder wall which tend to balance the side thrust of the piston within the cylinder and to maintain the piston axis subste ,ntially within the longitudinal plane of the engine containing the cylyieldingly urging the piston across inder axes.

It will be noted that I have provided a very simple structure for overcoming objectionable piston slap in an internal combustion engine for it is obvious that the thrufl ring 20 may be readily assembled with a piston of substantially standard construction, it bei g necessary to merely provide an additonal groove the piston for receiving the spring thrust ring.

Although I have illustrated but one form of my invention and have described in detail but a single application thereof, it will be apparent to those skilled in the art to which my invention pertains that various modifications and changes may be made therein without departing from the spirit of my invention or from scope of the appended claims.

What I claim as my invention is:

1. In a piston adapted to operate with clearance in an engine cylinder, a wrist pin, said piston having a circumierentially extending groove therein, and a spring ring secured in said groove and adapted for yielding engagement with the cylinder wall adjacent one end of said wrist pin for the cylinder l in a direction axially of said wrist pin, said ring having clearance with respect to the cylinder adja'cent the point where same is secured to the piston.

2. In a piston adapted to operate with clearance in an engine cylinder, a wrist pin, said piston have a circumferentially extending groove therein, and a spring ring non-rotatably fixed in said groove and adapted for yielding engagement with the cylinder wall confined to the regions thereof in the vicinity of one end of said wrist pin for yieldingly urging said piston across the cylinder in a direction axially of said wrist pin.

3. In a piston adapted to operate with clearance in an engine cylinder, at wrist pin, said piston having a circumferentially extending groove therein, and a spring ring non-rotatably secured in said groove and adapted for yielding engagement with the cylinder wall adjacent one end of said wrist pin for yieldingly urging said piston across the cylinder in a direction axially of said wrist pin, said ring having clearance with respect to the cylinder wall intermediate the ends of said wrist pin.

4. In a piston adapted to operate with clearance in an engine cylinder, a wrist pin, said piston having a circumferentially extending groove therein, and a split spring ring secured in said groove, the free ends of said ring being adapted for yielding engagement with the cylinder wall adjacent one end of said wrist pin for yieldingly urging the piston across the cylinder in a direction axially of said wrist pin.

5. In a piston adapted to operate with clear ance in an engine cylinder, a wrist pin, said piston having a circumferentially extending groove therein, a split spring ring in said groove, and fastening means securing the middle section of said split ring to piston whereby the free ends of said ring are adapted for yielding engagement with the cylinder wall adjacent one end of said wrist pin for yieldingly urging the piston across the cylinder in a direction axially of said wristpin.

6. In a piston adapted to operate with clearance in an engine cylinder, at wrist pin, said piston having a circumierentially extending groove therein, and a split spring ring secured in said groove and including oppositely extending arm portions encircling said piston, the free end portion of each arm portion being adapted for yielding engagement with the cylinder wall adjacent one end of said wrist pin for yieldingly urging the piston across the cylinder in a direction axially of said wrist pin.

7. In a piston adapted to operate with clearance in an engine cylinder, a wrist pin, said piston having a circumferentially extending groove therein, and a split spring ring secured in said groove and including oppositely extending tapered arm portions encircling said piston, the

free end portion of each arm portion being adapted for yielding engagement with the cylinder wall adjacent one end of said wrist pin for yieldingly urging the piston across the cylinder in a direction axially of said wrist pin.

87 In a piston adapted to operate with clearance in an engine cylinder, a wrist pin, said piston having a circumferentially extending groove therein, a split spring ring in said groove, and a pin for securing the middle portion of said ring to said piston whereby to provide oppositely extending spring arms, the free end portion of each arm portion being adapted for yielding engagement with the cylinder wall adjacent one end of said wrist pin for yieldingly urging the piston across the cylinder in a direction axially of said wrist pin.

9. In a piston adapted to operate with clearance in an engine cylinder, a wrist pin, said piston having a circumferentially therein, and a spring ring secured in said groove and adapted for yielding engagement solely with the cylinder wall adjacent one end of said wrist pin for yieldingly urging said piston across the cylinder in a direction axially of said wrist pin 1 extending groove into yielding engagement with the cylinder wall adjacent to the other end of said wrist pin.

10. A non-slap piston for an internal combustion engine, said piston having a circumferentially extending groove therein, a split ring in said groove, and fastening means securing said split ring to said piston whereby to provide oppositely extending arms adapted for exerting a force radially outwardly of the piston, the outer face of said ring being spaced radially inwardly of piston surface at point of. attachment.

11. A non-slap piston constructed for cooperaative assembly within the cylinder of an internal combustion engine, said piston having a circumferentially extending groove therein, a spring ring non-rotatably fixed in said groove and adapted for yielding engagement with the cylinder wall of said engine, said ring being fixed to radially space the outer face of the ring inwardly of the piston surface at point of attachment.

12. A non-slap piston constructed for cooperative assembly within the cylinder of an internal combustion engine, said piston having a circumferentially extending groove therein, a split spring ring secured in said groove, the free ends of said ring being adapted for yielding engagement with the cylinder wall adjacent that portion of the piston constructed for supporting a wrist pin for yieldingly urging the piston across the cylinder in a direction axially of the wrist pin supporting structure, said ring having a clearance with respect to said cylinder intermediate the ends of the Wrist pin.

13. A non-slap piston constructed for cooperative assembly within the cylinder of an internal combustion engine, said piston having a circumferentially extending groove therein, a split spring ring in said groove, and fastening means securing the middle portion of said split ring to said piston whereby the free ends of said ring are adapted for yielding engagement with the cylinder Wall, said middle portion of the ring having clearance with the cylinder Wall.

14;. A non-slap piston constructed for cooperative assembly within the cylinder of an internal combustion engine, said piston having a circumferentially extending groove therein, and axially aligned wrist pin bearing portions, a split spring ring in said groove, and fastening means securing the middle portion of said split ring to said piston whereby the free ends of said ring are adapted for yielding engagement with the cylinder wall adjacent one of said wrist pin bearing portions for yieldingly urging the piston across the cylinder in a direction substantially axially of said wrist pin bearing portions.

15. A non-slap piston constructed for cooperative assembly within the cylinder of an internal combustion engine, said piston having a circumferentially extending groove therein and axially aligned wrist pin bearing portions, and a split spring ring secured in said groove and including oppositely extending arm portions encircling said piston, the free end portion of each arm portion being adapted for yielding engagement with the cylinder wall adjacent one of said wrist pin bearing portions for yieldingly urging the piston across the cylinder in a direction substantially axially of said wrist pin bearing portions.

16. A non-slap piston constructed for cooperative assembly within the cylinder of an internal combustion engine, said piston having a circumferentially extending groove therein and axially aligned wrist pin bearing portions, and a split spring ring secured in said groove and including oppositely extending tapered arm portions encircling said piston, the free end portion of each arm portion being adapted for yielding engagement with the cylinder wall adjacent one of said wrist pin bearing portions for yieldingly urging the piston across the cylinder in a direction substantially axially of said wrist pin bearing portions.

17. A non-slap piston constructed for cooperative assembly within the cylinder of an internal combustion engine, said piston having a circumferentially extending groove therein and axially aligned wrist pin bearing portions, a split spring ring in said groove, and a pin for securing the middle portion of said ring to said piston whereby to provide oppositely extending spring arms, the free end portion of each arm portion being adapted for yielding engagement with the cylinder wall' adjacent one of said wrist pin bearing portions for yieldingly urging the piston across the cylinder in a direction substantially axially of said Wrist pin bearing portions.

18. A non-slap piston constructed for cooperative assembly within the cylinder of an internal combustion engine, said piston having a circum- Eerentially extending groove therein and axially aligned wrist pin bearing portions, a split spring ring in said groove, and fastening means for securing the middle portion of said ring to the piston, said fastening means located substantially in a plane containing the axes of the piston and the wrist pin bearing portions, the free ends of said ring being adapted for yielding engagement with the cylinder wall adjacent one of said wrist pin bearing portions for yieldingly urging the piston across the cylinder in a direction substantially axially of said wrist pin bearing portions.

19. A non-slap piston constructed for cooperative assembly within the cylinder of an internal combustion engine, said piston having a circumferentially extending groove therein and axially aligned wrist pin bearing portions, a split spring ring in said groove, and fastening means for securing the middle portion of said ring to the piston, said fastening means located substantially adjacent one of said wrist pin bearing portions, the free ends of said ring terminating substantially adjacent the other of said wrist pin bearing portions and adapted for yielding engagement with the cylinder wall for yieldingly urging the piston across the cylinder in a direction substantially axially of said wrist pin bearing portions.

20. A non-slap piston constructed for cooperative assembly within the cylinder of an internal combustion engine, said piston having a circumferentially extending groove therein and axially aligned wrist pin bearing portions, a split spring ring in said groove, and fastening means for securing the middle portion of said ring to the piston, said fastening means located substantially adjacent one of said wrist pin bearing portions whereby to provide oppositely extending arcuate spring arms terminating substantially adjacent the other of said wrist pin bearing portions, the free ends of each arcuate arm portion being adapted for yielding engagement with the cylinder wall for yieldingly urging the piston across the cylinder in a direction substantially axially of said wrist pin bearing portions.

21. A non-slap piston constructed for cooperative assembly within the cylinder of an internal combustion engine, said piston having a circumferentially extending groove therein, a spring ring secured in said groove and adapted for yielding engagement with the cylinder wall of said engine substantially adjacent that portion of the piston diametrically opposite to the point where said ring is secured to the piston, said ring having clearance with the cylinder at points other than those portions which yieldingly engage the cylinder Wall.

22. In an engine piston adapted to operate in a cylindrical structure and being subjected to side thrusts substantially in a plane containing the piston axis, means including a ring carried by said piston yieldingly engaging said cylindrical structure whereby to urge movement of said piston substantially in a plane transverse to the first said plane, said ring having a clearance with said HAROLD I-I. TIMIAN. 

